1. Field of the Invention
The present invention relates to an information processing system including a plurality of processors and a memory managing method used in the information processing system.
2. Description of the Related Art
Conventionally, computer systems such as server computers have utilized system architecture such as a multiprocessor and a parallel processor in order to improve in throughput. Both of the multiprocessor and parallel processor achieve a parallel computing operation using a plurality of processing units.
Jpn. Pat. Appln. KOKAI Publication No. 10-143380 discloses a computer system having a plurality of processing units. This computer system includes a single high-speed CPU, a plurality of low-speed CPUs and a shared memory. Processes are assigned to the high-speed and low-speed CPUs in consideration of parallelism and execution time of each process.
Not only the computer system but also an embedded device, which needs to process a large amount of data such as AV (audio video) data in real time, has recently required that system architecture such as a multiprocessor and a parallel processor be introduced to improve in throughput.
Under the present circumstances, however, a real-time processing system that is predicated on the above system architecture including a plurality of processors is hardly reported.
In a real-time processing system, each operation needs performing under given timing constraint. If, however, system architecture such as a multiprocessor and a parallel processor is applied to the real-time processing system, there occurs a problem that the performance of each of the processors cannot be used sufficiently because of the conflict of access with a shared memory, the constraints of the bandwidth of a memory bus and the like. Moreover, communications for transferring data between threads executed by different processors are carried out through a buffer on the shared memory. Therefore, latency associated with the communications between the threads that are frequently interacting with each other becomes a serious problem.